a6 THEORY OF ORGANIC EVOLUTION. 



we are restricted to visible characters. Hence a 

 knowledge of the nature of an organism presup- 

 poses a complete investigation of its characters in 

 their succession during the whole ontogeny. The 

 results must, however be tested and completed by 

 comparison with other organisms and by the most 

 comprehensive experimental procedure, possible, (as 

 by culture under various conditions, and crossing 

 with nearer and more remote relatives). The char- 

 acteristics of nutrition varieties and accidental 

 crosses must be separated from specific characteris- 

 tics by experimental procedure, and latent deter- 

 minants must be brought out by the same means. 



15. REPRODUCTION, AND RELATION BETWEEN PARENTS 



AND OFFSPRING. 



Reproduction is nothing more than a transition 

 from one generation to the next following, medi- 

 ated by the idioplasm of the germ cell. In asexual 

 (monogenic) reproduction there is continuity of the 

 same idioplasm. Therefore the parent continues in 

 the offspring its specific life, as the stem continues 

 its specific life in the branch. All the peculiarities 

 conditioned by the idioplasm remain unchanged in 

 the offspring. The latter, as the immediate con- 

 tinuation of the preceding ontogeny, starts from the 

 point at which the germ cell left it, so that immedi- 

 ately after the germ cell is separated at the close of 

 the ontogeny or before, the offspring passes at one 



